My regular stick is a 66" Sans Rival SR2, but I friend of mine has just purchased a 2012 Radar Senate 67" (due to the current closeout pricing).
I had a set on the Senate this morning and wow I was impressed. The ski did ride higher in the water than my SR2, but it didn't lose much feel/security in the turns as a result.
It maintained speed really well, and although it isn't as fast as my SR2, generating the speed is almost effortless.
The turning was a nice surprise... I usually don't like skiing on skis larger than 66" (I'm 70kg) due to the increased turn radius and decreased response of the ski, but the edge change was smooth and the turning tight and predictable.
This ski does some things better than my old Sixam SS, so I'm amazed of the performance vs the price.
Don't get me wrong, I wouldn't replace my SR2 with this (for course skiing), but I'm tempted to buy one for open water skiing, to get my flow on!